The men of B Company were in a dangerous state of mind. They had lost five men in a firefight the day before. The morning of Feb. 8, 1968, brought unwelcome orders to resume their sweep of the countryside, a patchwork of rice paddies along Vietnam’s central coast.

They met no resistance as they entered a nondescript settlement in Quang Nam province. So Jamie Henry, a 20-year-old medic, set his rifle down in a hut, unfastened his bandoliers and lighted a cigarette.

Just then, the voice of a lieutenant crackled across the radio. He reported he had rounded up 19 civilians and wanted to know what to do with them. Henry recalled the company commander’s response: ‘Kill anything that moves.’

Henry stepped outside the hut and saw a small crowd of women and children. The shooting began. Moments later, the 19 villagers lay dead or dying.

Back home in California, Henry published an account of the slaughter and held a news conference to air his allegations. Yet he and other Vietnam veterans who spoke out about war crimes were branded traitors and fabricators. No one was ever prosecuted for the massacre.

Now, nearly 40 years later, declassified Army files show that Henry was telling the truth — about the Feb. 8 killings and a series of other atrocities by the men of B Company.

The files are part of a once-secret archive assembled by a Pentagon task force in the early 1970s. It shows confirmed atrocities by U.S. forces in Vietnam were more extensive than previously was known.

The documents detail 320 alleged incidents that were substantiated by Army investigators — not including the most notorious U.S. atrocity, the 1968 My Lai massacre.

Although not a complete accounting of Vietnam war crimes, the archive is the largest such collection to surface to date. It includes investigative files, sworn statements by witnesses and status reports for top military brass.

The records describe recurrent attacks on ordinary Vietnamese. Hundreds of soldiers, in interviews with investigators and letters to commanders, described a violent minority who murdered, raped and tortured with impunity.

Abuses were not confined to a few rogue units, a Los Angeles Times review of the files found. They were uncovered in every Army division that operated in Vietnam.

Retired Brig. Gen. John H. Johns, a Vietnam veteran who served on the task force, said he once supported keeping the records secret but now believes they deserve wide attention in light of alleged attacks on civilians and abuse of prisoners in Iraq.

Investigators determined that evidence against 203 soldiers accused of harming Vietnamese civilians or prisoners was strong enough to warrant formal charges. These “founded” cases were referred to the soldiers’ superiors for action.

Ultimately, 57 of them were court-martialed and just 22 convicted, the records show.

Fourteen received prison sentences ranging from six months to 20 years, but most won significant reductions on appeal.

Many substantiated cases were closed with a letter of reprimand, a fine or, in more than half the cases, no action at all.

There was little interest in prosecuting Vietnam war crimes, said Steven Chucala, who in the early 1970s was legal adviser to the commanding officer of the Army’s Criminal Investigation Division. He said he disagreed with the attitude but understood it.

“Everyone wanted Vietnam to go away,” said Chucala, now a civilian attorney for the Army at Fort Belvoir in Virginia.

Top Army brass should have demanded a tougher response, said retired Lt. Gen. Robert G. Gard, the highest-ranking member of the Pentagon task force in the early 1970s.

“We could have court-martialed them but didn’t,” Gard said of soldiers accused of war crimes. “The whole thing is terribly disturbing.”